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garou81
Joined: 25 Jan 2023 Posts: 10 Location: Norther California
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Link Posted: Thu Jan 26, 2023 6:16 am Post subject: crt projector in rear projection cabinet |
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Hi Guys,
Just discovered CRT projectors and this site and its my new obsession. I have a couple questions. Would it be possible to take a smaller crt projector like a Dwin500 and install it inside of a 50" rear projection TV cabinet. Could something like that work.
I plan to get multiple projectors but I dont have the space for 2 80" screens.
Second question how can I gauge how bright lumens are? I want to add light to my media room but how will I know how much ambient light is too much?
Thanks for any advice
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Link Posted: Thu Jan 26, 2023 6:47 am Post subject: |
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Get a second RPTV put the mirror in the bottom of the 50" and put the projector behind the TV aiming at the mirror. It'll do a double bounce.
If you want a bright picture with a front projection look for a curved screen with a high gain.
Welcome to the forum.
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garou81
Joined: 25 Jan 2023 Posts: 10 Location: Norther California
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Link Posted: Thu Jan 26, 2023 1:58 pm Post subject: |
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So If I understand you correctly ill have a rear projection tv with 2 mirrors inside, one above and one below. I would then mount the projector facing down behind the cabinet. Then the beam bounces off the bottom mirror to the top mirror and should theoretically project as a rear projection tv normally would, Is that right?
Do I need to modify or change the existing screen components like the lenticular or fresnel lenses
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kal Forum Administrator
Joined: 06 Mar 2006 Posts: 17860 Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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Link Posted: Thu Jan 26, 2023 3:19 pm Post subject: |
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Welcome to the forum!
So the main issues with throwing a CRT projectors inside a RPTV style box are:
(a) Heat. Make sure to keep the CRT projector cool.
(b) Throw distance. CRT projectors come stock with lenses meant for a specific throw distance typically used in floor or ceiling setups where they project on a wall/screen. Inside that RPTV box the throw distance will be incredibly short so you'd need special short throw lenses, which don't usually exist as that was not the original intent for the CRT projector. Back when RPTVs used CRT they would have come with very short throw lenses and/or use a mirror as well to extend the throw slightly. This is what AnalogRocks talks about (bouncing off two mirrors to extend throw).
To measure lumens, use an illuminance meter: https://amzn.to/3kzen19
You asked how much ambient light is ok... With any front projector setup projector (CRT, digital, etc) the colour black comes from projecting nothing, i.e. having no ambient light. So with any projector setup you want to eliminate / reduce ambient light as much as possible including any light bounce back on to the screen. If you're doing RPTV it's a bit more forgiving as you're inside a (hopefully) black box. Some will line the inside of the box with velvet or similar to minimize any light bounce inside.
Kal
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garou81
Joined: 25 Jan 2023 Posts: 10 Location: Norther California
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Link Posted: Thu Jan 26, 2023 7:42 pm Post subject: |
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kal wrote: | Welcome to the forum!
(b) Throw distance. CRT projectors come stock with lenses meant for a specific throw distance typically used in floor or ceiling setups where they project on a wall/screen. Inside that RPTV box the throw distance will be incredibly short so you'd need special short throw lenses, which don't usually exist as that was not the original intent for the CRT projector. Back when RPTVs used CRT they would have come with very short throw lenses and/or use a mirror as well to extend the throw slightly. This is what AnalogRocks talks about (bouncing off two mirrors to extend throw).
To measure lumens, use an illuminance meter: https://amzn.to/3kzen19
You asked how much ambient light is ok... With any front projector setup projector (CRT, digital, etc) the colour black comes from projecting nothing, i.e. having no ambient light. So with any projector setup you want to eliminate / reduce ambient light as much as possible including any light bounce back on to the screen. If you're doing RPTV it's a bit more forgiving as you're inside a (hopefully) black box. Some will line the inside of the box with velvet or similar to minimize any light bounce inside.
Kal |
Thanks for the welcome both of you guys.
My RPTV is crt and does use a mirror So a second mirror is not what AnalogRocks is talking about he's talking about the actual throw lense to the mirror then.
About the ambient light What you explained about makes sense but I was more curios about the difference between say 800 lumens and 1200 lumens. But from your response it sounds like it just makes the picture overall brighter but any ambient light has potential to ruin the black. Having a 1300 lumen projector will not allow me to have more light in the room than a 600 lumen projector
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kal Forum Administrator
Joined: 06 Mar 2006 Posts: 17860 Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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Link Posted: Thu Jan 26, 2023 9:07 pm Post subject: |
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garou81 wrote: | About the ambient light What you explained about makes sense but I was more curios about the difference between say 800 lumens and 1200 lumens. |
400 lumens.
In all seriousness, lumens is a measure of light output: The higher the number, the brighter the source.
There are different "types" of lumens too that don't always compare one of one. For example. ANSI lumens are a popular way to measure display devices like projectors and so forth. Different from "regular" lumens.
Quote: | But from your response it sounds like it just makes the picture overall brighter but any ambient light has potential to ruin the black. |
Correct.
Quote: | Having a 1300 lumen projector will not allow me to have more light in the room than a 600 lumen projector |
Well, yes and no. In an ideal world you don't want any light other that the projector to shine on the screen. But many will use projectors in rooms that do not have great light control, or even use projectors outside when it isn't maybe completely dark or there's other light sources hitting the screen a bit. Or sometimes even projectors at shows/venues where there's LOTS of ambient light. To fight that you just throw more light at it. It's all about contrast ratio (ratio of black to white). The brighter your projector (i.e. the higher the lumens) the more that projector can fight against other light hitting the screen to get a picture that is acceptable with an acceptable contrast ratio. So if you raise the black level (min light) you have to also raise the white level (max light) to keep the contrast ratio the same. The brighter the projector the larger the screen you can have too before the amount of light drops off to unacceptable levels.
Acceptable is of course completely up to the end user though there are some standards to what's acceptable. From our GREYSCALE FOR DUMMIES guide:
Projectors (CRT and digital): 12-16 ftL*
Direct view sets (CRT tube, Plasma, rear projection, flat panel, etc.): 30-40 ftL
(light output on screen is typically measured in foot lamberts (ftL) instead of lumens)
Kal
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Link Posted: Fri Jan 27, 2023 12:29 am Post subject: |
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OK to clarify, you would remove the existing projector from the CRT cabinet in place of the existing projector you woudd put a mirror. at a 45 deg angle. Ther would be a hole in the back of the cabinet. The projector would be sitting on the floor behind the RPTV beaming into the mirror.
You may still need shorter throw lenses like Kal said
OR
Try it your way mount the projector pointed down, then add 2 mirrors. Bounce off the first one at 45 degrees outside the cabinet, then the light hits the second mirror bounces at 45 degrees onto the original mirror inside the cabinet and onto the original rear projection screen.
That would be a fun experiment.
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virusc
Joined: 11 Apr 2007 Posts: 322 Location: Massachusetts
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Link Posted: Fri Jan 27, 2023 2:36 pm Post subject: |
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I have tried this and I have to say don't do it. The reason is the electronic geometry correction from a front projector is not made for the small size and toe in angles of such a small screen. Also what Kal said. I tried it with a Barco 500 and a sony 10xx and even though they had enough range to make it work they drifted a lot due to being at the maximum adjustment for keystone/etc.... Also this is a lot of work and you are better off just finding one. Someone was selling a 45" or 50" sony nearly new RP set that was based off of the 1252 chassis for nearly nothing last year. The dwin 500 is a really compact unit and I would not mess with it. It throws a good pic if the tubes are not tired. Why not just install it on the ceiling and be done with it? I have seen setups where people had multiple CRT ceiling setups for whatever reason.
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garou81
Joined: 25 Jan 2023 Posts: 10 Location: Norther California
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Link Posted: Fri Jan 27, 2023 3:53 pm Post subject: |
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virusc wrote: | I have tried this and I have to say don't do it. The reason is the electronic geometry correction from a front projector is not made for the small size and toe in angles of such a small screen. Also what Kal said. I tried it with a Barco 500 and a sony 10xx and even though they had enough range to make it work they drifted a lot due to being at the maximum adjustment for keystone/etc.... Also this is a lot of work and you are better off just finding one. Someone was selling a 45" or 50" sony nearly new RP set that was based off of the 1252 chassis for nearly nothing last year. The dwin 500 is a really compact unit and I would not mess with it. It throws a good pic if the tubes are not tired. Why not just install it on the ceiling and be done with it? I have seen setups where people had multiple CRT ceiling setups for whatever reason. |
Yeah... If I could just decase the projector and swap the lenses that would be one thing. I don't want to wind up destroying a perfectly good front projector and rear projector. I just like the idea of the portability of the RPTV combined with the versatility of the front projector.
What model sony RPTV is based off the 1252?
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virusc
Joined: 11 Apr 2007 Posts: 322 Location: Massachusetts
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Link Posted: Fri Jan 27, 2023 4:28 pm Post subject: |
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Sorry I really don't remember and you don't see these all the time but Sony had really good ones based off of 12xx line that were all the way down to I think 40". If you could fine one of those it would be great as their are plenty of parts and tubes floating around for them compared to most of the others. Also, they look very similar to the 1990's sets so they are easy to miss if searching. I also setup RP using mirrors for commercial installs but like I said before nearly all the manufactures FP/RP CRT projectors were not made to go down below 60" and even that was small. You can have a open back setup with no RP walls with just the mirror and screen as well but the stuff around the projector needs to be dark/black otherwise you will get reflections.
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Link Posted: Sat Jan 28, 2023 12:14 am Post subject: |
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You could try fitting the RPTV lenses to the external projector. All sorts of ways to experiment
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wanderer
Joined: 11 Jan 2015 Posts: 63
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barclay66
Joined: 27 Jun 2011 Posts: 1291 Location: Germany
TV/Projector: Marquee 9500 Ultra
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Link Posted: Sat Jan 28, 2023 5:11 pm Post subject: |
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I once had a Barco Graphics 801s which had originally been a RetroGraphics. What had remained from the Retro components were the LC tubes with curved C-Elements. These could be replaced with the colored ones from a Sony G70 and the lenses were HD-214 if I recall correctly. It had to be mounted a few feet closer to the screen but the picture was nicely sharp and vivid. At least for 8” tubes with electrostatic focus.
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garou81
Joined: 25 Jan 2023 Posts: 10 Location: Norther California
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Link Posted: Sun Jan 29, 2023 1:54 pm Post subject: |
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wow cool! Thanks for finding this. I'm sure all of these have been scrapped by now, but after having seen this it does seem a bit more feasible.
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Link Posted: Wed Feb 01, 2023 4:35 am Post subject: |
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I remember when those were coming out surplus about 10-12 years ago. Never could get my hands on one or three. Would have made my man cave a whole different room.
_________________ Tech support for nothing
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garou81
Joined: 25 Jan 2023 Posts: 10 Location: Norther California
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Link Posted: Wed Feb 01, 2023 3:17 pm Post subject: |
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Well guys I am now the proud owner of a sony vph-d50. I selected this projector because it was the smallest and was had favorable reviews. Got lucky and found a broadcast store 100 miles away from me that had this new from sony so I jumped on it. My first impression, This thing is a behemoth!!! It seems so much bigger than the dimensions indicate. The quality is just something you don't see today on retail products. I cant bring myself to cracking this thing open...I just cant. Any how I wanted to thank everyone for their help.
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kal Forum Administrator
Joined: 06 Mar 2006 Posts: 17860 Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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Link Posted: Wed Feb 01, 2023 3:34 pm Post subject: |
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garou81 wrote: | Well guys I am now the proud owner of a sony vph-d50. My first impression, This thing is a behemoth!!! |
That's interesting to read, given that it's one of the smallest CRT projectors out there. I remember seeing one for the first time in the mid 90s after seeing Barco 1209's and similar and thinking the opposite (how'd they fit all that in this tiny chassis!). Not quite as small as a Dwin, but not that far off...
Congrats on the find! Hopefully you got it for free...
Kal
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garyfritz
Joined: 08 Apr 2006 Posts: 12026 Location: Fort Collins, CO
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Link Posted: Wed Feb 01, 2023 5:53 pm Post subject: |
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Heck yeah, the D50 only weighed 120 lbs. Look at the larger Sony models: G70 weighed 183 lbs, and the G90 was 242 lbs! Now THAT'S a behemoth.
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AnalogRocks Forum Moderator
Joined: 08 Mar 2006 Posts: 26690 Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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Link Posted: Thu Feb 02, 2023 5:25 am Post subject: |
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I have one of those. I used it for years and I can bear hug it and move it my self. Mine has 6000-7000 hours on it and one repair. Been pretty good.
also handy because it can take VGA via RGBHV as most projectors but you can switch it to YPbPr/component input on those same BNC inputs and run 1080i ( NOT 1080P ) or 720P. I ran mine 1080i, it's a little easier for the projector to display and I ran 1024x768 from the lap top.
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garou81
Joined: 25 Jan 2023 Posts: 10 Location: Norther California
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Link Posted: Thu Feb 02, 2023 10:42 pm Post subject: |
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I was just picturing something in my mind the size of say 2 pc towers taped together. The shop i went to had a g90 in the window for display purposes i guess. That thing wouldn't have fit in the back of my midsize suv. The top panel was ajar and it kinda reminded me of the hood of a firebird. I just had no concept of how large these things were
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